A Beginner’s Guide to Window Insulation

20/12/2018

No Comments

774

As well as letting light into your property, windows should offer sufficient thermal insulation. Without the right window insulation, your home can become cold and draughty – especially through the winter. So, what can you do about it?

In this post, we discuss every aspect of window insulation, from why it’s important to how you can improve it.

The thermal envelope

Every building has a thermal envelope, which is a physical barrier between the conditioned interior and the unconditioned exterior of the property. It’s made up of the floor, walls and roof along with doors and windows.

When you think of your property’s heat insulation, most people correctly consider the floor, walls and the roof. That’s why the likes of loft and cavity wall insulation are so popular. However, it’s not uncommon for property owners to overlook a building’s fixtures.

In terms of heat retention, this can be devastating. Even with the most well-insulated walls, poorly insulated windows will draw warm air out of a building and let the cold air in. After all, they typically make up around 20 percent of walls’ surface area.

Problems with window insulation

There are a range of factors which can contribute to a window’s thermal insulation efficiency.

Poor glazing

The most common cause of window insulation problems is inefficient glazing. Essentially, if the glass doesn’t form an insulative barrier between the inside and outside of your home, it’s not doing its job. Single glazing has this problem because the single pane of glass becomes cold on the inside as the outside temperature drops.

Double glazing aims to solve this problem, by using two panes of glass with an insulative gap in between the two. However, this doesn’t always work, as there are additional problems that can occur even with double glazing in place…

Gaps around the frame

The next potential issue is window frame insulation. Regardless of your glazing type, there may be gaps around the window frame which let cold air in and warm air out. This could be a crack in the sealant between the frame and glass, or just damage to the frame itself.

Needless to say, this can make it near impossible to heat your property and maintain a comfortable temperature.

Closing mechanism not airtight

Another problem on some windows is the closing mechanism. Most windows have a hinged section or a sliding sash, which can be opened to keep your home well ventilated. However, they also need to be airtight when they close to maintain proper window insulation.

Any gaps in the moving section of your windows will allow cold air in and eliminate the insulation provided by the rest of the unit.

How to check window insulation

To test your windows’ thermal insulation, you essentially need to check for any of the points covered above.

Firstly, check the glazing itself by touching the inside of your windows. It’s best to try this on a cold day when the inside of your home is relatively warm. While they won’t be as warm as your home’s interior, they shouldn’t be as cold as the outside of the property.

To test for draughts around the window frame or closing mechanism, you can use a simple match test. Light a match and hold the flame carefully around each part of the window frame. If air is seeping in, it will blow the flame. This also works with an incense stick.

You can also check for moisture around the windows. When it’s raining outside, run your fingers around the frame to check for any dampness or droplets, along with wet patches on the windowsill. If water can get through the window frame, so too can cold air.

Improving window insulation

The good thing about window heat insulation is that it can be improved. Most sites you’ll find online will recommend new windows as a way to improve insulation. This should be treated as a last resort by property owners and isn’t necessarily the best option. For one, it’s out of the question if your property is listed or you just want to maintain its heritage appearance.

Fortunately, there are a range of options to strengthen the insulative barrier on existing windows and stop cold air seeping through.

1. Sealing off windows

If gaps in your window frame are causing poor insulation, it’s definitely worth having them re-sealed to see if it fixes the problem. One way of doing this is with caulking around the joints – between the frame and the wall. You can also try weather strips as a temporary solution. These are self-adhesive strips which can be applied on the inside of your windows for the same sealing effect.

If you have wooden window frames, you could also consider having any gaps or breaks repaired to eliminate the detriment to your windows’ insulation. While wood is liable to decay over time without the right maintenance, problems can be isolated and repaired by specialists if they’re caught early enough.

2. Dressing windows

Another option is to add insulation on the inside of your windows. Thick, lined curtains add an extra layer of insulation to your windows in winter, which can be easily removed or replaced with a lighter alternative in the warmer months.

Shutters work similarly, but can’t be removed as easily and block out a lot of light when used. As an additional measure, you can lay out draught snakes on your windowsill to stop some of the warm air escaping.

3. Transparent insulation for windows

When it comes to transparent window insulation, there are two options to choose from – secondary glazing and window insulation film.

To start with, insulation film is a plastic sheet which is applied on the inside of windows. After cutting to size, it simply needs to be heated to stick onto the surface of the window with a small improvement to your window’s insulation. The main downside here is that it’s not necessarily transparent. Insulation film can become cloudy, impacting the appearance of your windows.

On the other hand, secondary glazing improves thermal insulation by up to 60%. In simple terms, it means adding a discreet secondary window frame on the inside of existing windows. It has minimal impact on the aesthetics of windows, so you can maintain the style of your property. Best of all, it can reduce annual fuel bills by as much as 15%.

Get your window insulation kit

At Clearview, we provide high quality DIY secondary glazing kits for domestic and commercial customers across the UK. All kits are supplied fully assembled and installation-ready, with no preparation required on existing windows. Put simply, it’s an easy and effective way to improve the insulation of your windows.

Discover How To Stop Draughts for Good And Save On Your Energy Bills

This free eGuide – written by specialists – explains in simple terms how to improve the thermal efficiency of your windows by 60% and how you can reduce your yearly heating bill by 15%.

Simply enter your name and email below and we will send a free copy straight to your inbox.

First Name *

Email *

I give consent to use this information to send additional emails and communication as described in your Privacy Policy *

Clearview secondary glazing - the solution to significantly improved acoustic and heat insulation to your property, making your home or offices more comfortable, secure, greener and cost efficient to run. Achieved without the disruption of replacement windows, and without damaging the character of your building.

My client wanted a solution to a problem regarding excessive sound being experienced within a large office complex, whilst having conferences and meetings in a large second-floor room with single glazed aluminium windows on two elevations. During my research, I found Clearview to be knowledgeable and very helpful in solving my client’s problem and alternatives with prices to meet the budget available. I was provided quality support throughout the process. The product was delivered on time, as promised with good protective wrapping. The installation was extremely easy, with quality materials and instructions. Once installed, the difference was amazing and whilst showing the client the finished job, a very large articulated lorry being towed by a similarly large tow truck rolled past the conference room within 3 m. The silence was palpable, the client was over the moon and hopefully impressed enough to want this system throughout this large office complex. Watch this space! Many thanks to the Clearview team for making this such an easy process and special thanks to Lianne and Deborah for putting up with my blond moments during the survey and ordering stage. As a shopfitter/office refurbishment specialist, we provide a service and believe that the client is king and by providing a good service the client will happily use us again. Clearview have the same philosophy, sadly there are too many companies who do not.read more

Excellent service form start to finish, we are really happy with our new windows, the house is now much warmer and they have really reduced the noise levels from a near by road. The whole team at Clearview were very professional, the fitters were great and the whole experience was efficient and the windows fitted within a month. I would highly recommend Clearview to anyone looking for secondary glazing.read more

Good quality windows, accoustic glass does the job well. We fitted these ourselves, but the website and customer service team make sure you've been informed of everything you need to do to measure correctly and that you've chosen the right options for openings. Not the cheapest, but all in all great service, would recommend to anyone.read more

If you have an older house with "special" windows which are struggling to cope with our ever changing weather conditions, I recommend that you seriously consider Secondary Glazing. Have a look at Clearview's web site first as it is really helpful, then if you are in any doubt speak to them. The Ladies there are even more helpful. Do not rule out fitting them yourself as the quality of the units supplied is first class. The key to it success is in the measurement of the windows you wish to fit. Measure and then check again. I would recommend trying just one first before embarking on a full scale re-fit as it will give you more confidence in the product. I had a condensation problem in my downstairs cloakroom, so I tackled this first. It looked great and it solved the problem. You get expert help, they keep you up to date on delivery (always on time) and the end product is first class, at a fraction of the cost of new glazing. Highly recommended. Geoff Chipping Campdenread more

Hi guys, I recently bought some secondary glazing, which arrived on time, 7.00am, just before i went to work..excellent service, Ive just fitted them to my sash windows...They look great,so easy to fit!! Im over the moon with them, I would certainly recommend these windows to anyone.. All you have to do is remember to double check your measurements before ordering,,, I would say 3,- 4,hrs to fit 7 windows, Ne bother !!!!!! Thanx once again, Best regards. Syd Carr.... P,S. One double glazing company wanted nearly "double" what you guys charge,,,,read more

Our bedroom overlooks a railway line, so we were primarily looking for acoustic insulation (we’d had secondary glazing in our last home, so knew how effective it was). After some online research, we went with Clearview this time, as their prices are competitive, their online quotation system quick and easy, and – perhaps most importantly – their customer service responsive and helpful. As it happened, here were a couple of glitches (on my part) with measuring and specifying, which Andy at Clearview ironed out for me with no fuss. Once ordered, the product arrived on time, and has proved highly effective at reducing the noise. I actually enjoy watching trains go by in near-silence, and have since ordered a similar unit for our living room, to repeat the experience! I can thoroughly recommend secondary glazing in general, and Clearview in particular.read more

Bought 2 units for our front bedrooms as we are on a noisy main road. Installed them yesterday and the difference in noise is amazing. I went for the 6.4mm laminated glass and positioned the units on the front of the window sill to give maximum gap.read more